1. Field of the Invention
The invention relates to a chassis for a motor vehicle, having an electrical axle with two electrical machines and wheels rotatably mounted in the region of the two ends of the electrical axle. Each wheel to be driven by one of the electrical machines. A step-down gear mechanism is arranged between the respective electrical machine and the wheel associated with the electrical machine.
2. Description of the Related Art
DE 295 18 401 U1 discloses the above-described type of chassis used in a utility vehicle. This utility vehicle is a city bus for transporting people. A carriage floor is arranged at a low level of the city bus and runs through the entire bus, including the region of the rear axle, which is in the form of a rigid axle. To achieve this configuration, the electrical axle is a hollow portal axle and the two electrical machines are in the form of electric drive motors accommodated by the portal axle. A step-down gear mechanism in the form of a spur gear stage is arranged between the respective electrical machine and the wheel associated with the electrical machine. As an alternative, the electrical machines are mounted next to the portal axle. DE 296 11 867 U1 also discloses a chassis having the features of the type mentioned above.
DE 44 34 237 A1 discloses a vehicle axle having two electric single-wheel drives for agricultural vehicles. The two single-wheel drives can be connected in a force-fitting manner by means of a clutch to avoid overloading one single-wheel drive over a relatively long period of time in the event of non-uniform loading of the drive wheels of the vehicle axle. The respective electric single-wheel drive is connected to a step-down gear mechanism in the form of a spur gear stage. The step-down gear mechanism is connected to a planetary gear mechanism that is connected to the wheel associated with the single-wheel drive. The axle of the wheel is offset radially in relation to the rotation axis of the rotor of the electric motor. The electrical input energy for the respective electric motor is generated by a generator driven by the vehicle's own internal combustion engine.
DE 10 2004 003 634 A1 discloses a portal axle drive of a motor vehicle. Torque is introduced from a planetary gear mechanism via a step-down gear mechanism in the form of a spur gear stage and into an output shaft that is connected to the wheel in a rotationally fixed manner.
DE 202 13 670 U1 describes a directly driven drive axle of a motor vehicle having two electric drive motors mounted in a common housing.
The above-described chassis or axle designs disadvantageously relate to rigid portal axles. Chassis of this kind are reserved for use in utility vehicles, buses or agricultural vehicles for vibration and comfort reasons. Furthermore, electrical machines with coaxially arranged rotational axes do not permit any relevant change in length.
The object of the present invention is to provide a chassis of the kind mentioned above but with a separate connection from the respective wheel to the step-down gear mechanism that allows the wheel to be mounted in a non-rigid manner and that permits the overall length of the electrical machines to be varied.